1. Field of the Invention
This invention pertains generally to pump and valve controllers for irrigation and landscaping water systems, and more particularly to a circuit isolator apparatus for pump and master valve circuits which eliminates feedback and phasing problems which can occur when multiple controllers are included in a single circuit.
2. Description of the Background Art
Timed controllers are commonly used to provide power for operation of pumps or master valves in irrigation or landscaping water systems. Frequently, multiple controllers are tied to the same circuit for operation of a common pump or master valve. When the area to be irrigated is large, the individual controllers can be hundreds of yards apart.
Various problems arise when two or more controllers which are interconnected through the same circuit are operating at the same time. The problem of feedback or cross-talk between controllers on the same circuit can result in strange or unwanted behavior of the controllers such as unscheduled cycle starts and stops. Another problem experienced is incorrect phasing or reversed polarity of controllers, which can result in serious damage to multiple controllers on the circuit. A further problem is that, when a controller circuit breaker has been tripped due to a faulty solenoid, the circuit breakers on other controllers on the circuit may also be tripped by the same faulty solenoid upon activating the pump or valve circuit.
The feedback problem can be overcome through use of a separate pump relay for each controller. Manufacturers of irrigation controllers typically recommend that each controller on a circuit be wired to a separate relay at the pump or valve location where the contacts can switch to a separate power source individually or together, without interconnecting the controllers. In practice, however, the recommended relays are not used, since it is an expense which is easily eliminated during new construction. Even when a separate relay is used for each controller, the aforementioned problem of incorrect phasing of multiple controllers on a circuit may not be avoided. The use of good design practices and adherence to electrical codes can resolve phasing problems but, in order to reduce costs, this practice is not carried out.
Accordingly, there is a need for a circuit isolator apparatus for use in circuits wherein multiple controllers are interconnected through a pump or valve circuit which eliminates feedback and phasing problems, and which avoids unwanted tripping of multiple circuit breakers. The present invention satisfies those needs, as well as others, and generally overcomes the deficiencies found in the background art.